Hi,
Im working on a library to decode medical image files, and some of these
files are encoded as 'PALETTE COLOR', which means you have a lookup
table for red, green and blue pixel values. The final RGB pixel array is
constructed by hitting the lookup table with the original pixel values.
In my implementation I am using an iterator, and it is kinda slow. I
cant spot an obvious way to improve on it though, so I thought I'd put
the question out here and see if any of you more experienced Rubyists
can suggest a more efficient way of doing this.
Thanks,
Chris
Example code:
# Set up example arrays to test the algorithm:
lookup_values = Array.new
lookup_values << Array.new(256, 0)
lookup_values << Array.new(256, 1)
lookup_values << Array.new(256, 2)
pixels = Array.new(258000, rand(256))
rgb = Array.new(pixels.length*3)
# The PALETTE transformation algorithm:
pixels.each_index do |i|
rgb[i*3] = lookup_values[0][pixels[i]]
rgb[(i*3)+1] = lookup_values[1][pixels[i]]
rgb[(i*3)+2] = lookup_values[2][pixels[i]]
end
--
Posted via http://www.ruby-forum.com/.